Commit 63cdafe0 authored by Alistair Popple's avatar Alistair Popple Committed by Linus Torvalds
Browse files

kernel/resource: refactor __request_region to allow external locking 

Refactor the portion of __request_region() done whilst holding the
resource_lock into a separate function to allow callers to hold the lock.

Link: https://lkml.kernel.org/r/20210419070109.4780-2-apopple@nvidia.com


Signed-off-by: default avatarAlistair Popple <apopple@nvidia.com>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Muchun Song <smuchun@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d486ccb2

kernel/resource.c

+32 −20
Original line number Diff line number Diff line
@@ -1160,31 +1160,16 @@ struct address_space *iomem_get_mapping(void) 
	return smp_load_acquire(&iomem_inode)->i_mapping;

}



/**

 * __request_region - create a new busy resource region

 * @parent: parent resource descriptor

 * @start: resource start address

 * @n: resource region size

 * @name: reserving caller's ID string

 * @flags: IO resource flags

 */

struct resource * __request_region(struct resource *parent,

static int __request_region_locked(struct resource *res, struct resource *parent,

				   resource_size_t start, resource_size_t n,

				   const char *name, int flags)

{

	DECLARE_WAITQUEUE(wait, current);

	struct resource *res = alloc_resource(GFP_KERNEL);

	struct resource *orig_parent = parent;



	if (!res)

		return NULL;



	res->name = name;

	res->start = start;

	res->end = start + n - 1;



	write_lock(&resource_lock);



	for (;;) {

		struct resource *conflict;
@@ -1220,13 +1205,40 @@ struct resource * __request_region(struct resource *parent, 
			continue;

		}

		/* Uhhuh, that didn't work out.. */

		free_resource(res);

		res = NULL;

		break;

		return -EBUSY;

	}



	return 0;

}



/**

 * __request_region - create a new busy resource region

 * @parent: parent resource descriptor

 * @start: resource start address

 * @n: resource region size

 * @name: reserving caller's ID string

 * @flags: IO resource flags

 */

struct resource *__request_region(struct resource *parent,

				  resource_size_t start, resource_size_t n,

				  const char *name, int flags)

{

	struct resource *res = alloc_resource(GFP_KERNEL);

	int ret;



	if (!res)

		return NULL;



	write_lock(&resource_lock);

	ret = __request_region_locked(res, parent, start, n, name, flags);

	write_unlock(&resource_lock);



	if (res && orig_parent == &iomem_resource)

	if (ret) {

		free_resource(res);

		return NULL;

	}



	if (parent == &iomem_resource)

		revoke_iomem(res);



	return res;